1. Field of the Invention
The present invention relates to an optical recording medium recording/reproducing apparatus, and in particular to a data recording speed control apparatus and method for recording data on an optical recording medium. The present invention is capable of converting data inputted from a host into a recording format, recording the reformatted data on an optical medium at an initial speed, variably adjusting a recording format conversion speed of the data when a data input speed is changed, resetting the speed for recording the reformatted data on an optical recording medium, and recording and reproducing the reformatted data at the reset recording speed.
2. Description of the Background Art
FIG. 1 is a view illustrating a conventional optical recording medium recording/reproducing apparatus. As shown therein, the conventional optical recording medium recording/reproducing apparatus includes an interface unit 30 for receiving data from an external host 32 and transferring the same to a buffer 19, a digital recording signal processor 20 for converting data from the buffer 19 into a certain recording format by providing an error correction code to the data from the buffer 19, a bit encoder 21 for converting the recording format data into bit stream data, a laser diode driving unit 22 for driving a laser diode by providing a driving voltage corresponding to the bit stream data to the laser diode, an optical pick-up unit 11 for recording data onto an optical recording medium 10 and reading the recorded data, a motor driving unit 18 for driving a spindle motor 12, an amplifier 13 for amplifying a wobble signal of the optical recording medium 10 read from an auxiliary beam of the optical pick-up unit 11 at a certain level, a wobble data detector 14 for detecting wobble data corresponding to an amplified low frequency wobble signal, a ATIP synchronous signal detector 15 for detecting an ATIP synchronous signal from the detected wobble data, a reference ATIP synchronous signal generation unit 17 for generating a reference ATIP synchronous signal, an error detector 16 for detecting a phase difference between an ATIP synchronous signal from the ATIP synchronous signal detector 15 and a reference ATIP synchronous signal from the reference ATIP synchronous signal generation unit 17, a motor driving unit 18 for varying the data recording speed of an optical recording medium by applying a driving voltage corresponding to the detected phase difference to the spindle motor 12, and a microcomputer 25 for receiving wobble data from the wobble data detector 14, controlling variably the data conversion speed of the digital recording signal processor 20 and controlling operation of the laser diode driving unit 22.
The operation of the thusly constituted optical recording medium recording/reproducing apparatus will now be explained.
First, when a data record is requested from the host 32 (for example, PC) for recording onto an optical recording medium, the data outputted from the host 32 via the interface unit 30 is temporarily stored in the buffer 19. When buffer 19 stores the inputted data, the digital recording signal processor 20 sequentially reads out the data temporarily stored in the buffer 19 and outputs it to the bit encoded 21 at an initial speed.
The bit encoder 21 converts the processed signal data into a bit stream and outputs it to the laser diode driving unit 22, and the laser diode driving unit 22 outputs a driving voltage corresponding to the bit stream to a laser diode of the optical pick-up unit 11. Then, the laser diode scans the main laser beam across the recording surface of the optical recording medium in accordance with the driving voltage corresponding to the bit stream, thereby recording the inputted data.
While the inputted data is being recorded on the optical recording medium, an auxiliary beam formed on the recording surface of the optical recording medium detects a low frequency wobble signal from the optical recording medium together with the main beam, and the detected low frequency wobble signal is amplified to a certain level by the amplifier 13. A shown in FIG. 2, corresponding wobble data is detected by the wobble data detector 14.
As shown in FIG. 3A, when a reference ATIP synchronous signal is outputted from the reference ATIP synchronous signal generation unit 17, as shown in FIG. 3B, the ATIP synchronous detector 15 generates an ATIP synchronous signal whenever the ATIP synchronous detector 15 detects a ATIP synchronous signal. The error detector 16 compares a phase difference between the ATIP synchronous signal and the reference ATIP synchronous signal. As shown in FIG. 3C, error amounts e1 and e2 are detected.
The thusly detected error amounts e1 and e2 are applied to the motor driving unit 18, and as shown in FIG. 3D, the motor driving unit 18 applies a driving voltage corresponding to the error amount to the spindle motor 12, so that a recording speed of the recording/reproducing apparatus is controlled, and the recording speed based on the main beam is maintained. The ATIP synchronous signal is compared with the reference signal. As a result of the comparison, if the pulse width of the ATIP synchronous signal is larger than the pulse width of the reference signal, as shown in FIG. 3D, the motor driving unit 18 accelerates the spindle motor by the error amount e1, and on the contrary, the spindle motor is decelerated by the error amount e2. Therefore, the recording/reproducing apparatus of the optical recording medium uniformly maintains the recording speed of the data irrespective of the speed of the data inputted.
In the conventional recording/reproducing apparatus of the optical recording medium, when reproducing the data recorded on the optical recording medium, the reproducing speed variable operation is performed in the same manner as the recording speed variable operation.
However, when data is inputted from the host 32 and recorded data is reproduced at an initial speed for a certain period, the recording speed is varied based on the synchronous detection speed of the wobble data detected so that an initial recording speed is maintained and controlled.
At this time, when the data output speed from the host 32 is sharply increased or decreased, an error occurs in the recording operation of the optical recording medium recording/reproducing apparatus which operates at a uniform recording speed. In particular, in the case that the initial recording speed is high (e.g., 4×, 6×, 8×), when the host 32 performs an e-mail transmission or operates based on an internal interrupt operation, the data output speed of the host 32 is decreased. At this time, if there is no data inputted in the buffer 30, since a uniform recording speed of the optical recording medium recording/reproducing apparatus is maintained, the data may be incorrectly recorded, thereby causing a fatal error in the optical recording medium.